FI106670B - Reception procedure and recipients - Google Patents

Description

, 106670

Reception method and receiver

Field of the Invention

The present invention relates to a receive method using a TDMA multiple access method, which receives signals placed in time slots for establishing connections, and in which the transmitted signals are received at different intensities from the time slots, and in which the received signals are amplified by a certain magnification factor.

Background of the Invention

In a radio system, subscriber terminals, such as a cellular telephone, are located at different distances from the base station. The propagation attenuation causes the transmitted signal to be attenuated, whereby signals transmitted at the same transmission power arrive at the receiver with different power. The various interference signals produced by the reflection of the signal may be summed up in the opposite phase to the information signal, whereby the information signal is increasingly attenuated. The more distant the transmitter and receiver are, the more obstacles the attenuator may receive. If the signal is attenuated. . enough, the connection between the subscriber terminal and the access point may be lost or the connection may not • be established.

i In radio systems, connections are made using signals of different frequencies. In addition, the signals may be transmitted by interleaving them appropriately into time slots. In prior art solutions, the frequency allocation during a call is made such that the subscriber terminals located far from the base station are allocated to use a particular frequency. The signal propagated over a long distance on the radio path has typically had to be greatly amplified. ···. 25 in the receiver. The subscriber terminals located near the base station are allocated to the user. t another frequency that is different from the signal used by the remote subscriber terminal. If the signal has had a short distance from the transmitter to the receiver, then the signal is typically only slightly amplified at the receiver.

• · ·: ·! 30 Radio system base station receivers commonly used • · ·; i>; digital tuners. Typically, the receiver comprises a plurality of tuners, by means of which it has been possible to divide the dynamic range of the receiver into smaller parts. Each tuner has formed its own part of the dynamic range of the entire receiver. The receivers have practically covered different frequency-35 ranges, whereby the receivers have been able to collectively receive a signal of 10666670 from a predetermined frequency band. In this way, the dynamic range of the base station has been greatly increased.

In addition, base stations use broadband multicarrier radios, which provide base stations of smaller size, lighter weight, and lower cost. Multi-carrier radios allow for improved access to various base station functions, giving the base station more flexibility in operation. If the base station receives signals of very different power, it is not possible to use Automatic Gain Control (AGC) at the receiver, since it is virtually impossible to reduce the gain solely on the basis of a strong signal. As a result of the above, in the above situation, the weak signal cannot be received at all. Similarly, due to a weak signal, it is not practically possible to increase the gain, because then a strong signal would be amplified too much and distorted.

15 The lack of automatic gain control requires a very large dynamic range of the receiver. For example, in a GSM system, the dynamic range of a base station receiver should be in the order of 100 dB. With current technology, a dynamic area of the above size can be implemented. : what is impossible. In particular, the receiver A / D conversion is performed by: *, · *. The components restrict the increase of the dynamic range.

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BRIEF DESCRIPTION OF THE INVENTION

It is therefore an object of the invention to provide a receiving method and a '·· receiver so that the above problems can be solved. This is achieved by a reception method of the type described in the introduction, characterized by forming at least two time slot groups using different gain coefficients and amplifying the signals received from the same time slot in the same time slot, and the forming signal is placed in a time interval group to measure the strength of the received signal, and the · · · · 30 connecting signal is placed in the time slot group based on the signal strength measurement of the received signal -: \ # L.

....: The invention further relates to a receiver for use in a TDMA radio system, which receives signals placed in time slots for communication by the receiver, and which receives signals of different intensity in the time slots, and which comprises amplifier colors. , which amplify the received signals with a certain magnification factor.

The receivers are characterized in that the receiver is adapted to receive connection signals from time slots and to form at least two time slot groups, and , which measure the strength of the signal received by the receiver, and positioning means which place the connection signal in a time slot group based on the strength measurement made on the received signal.

Preferred embodiments of the invention are claimed in the dependent claims.

The invention is based on the fact that the time slot used in the connection between the transmitter and the receiver is determined on the basis of a measurement made on the signal received by the receiver.

With the receiving method of the invention and the receiver ·. ; several benefits are achieved. The method allows receivers to receive

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. *. * 20 provides signals in the same, different, or overlapping frequency ranges.

: 'V This way you can increase the number of channels. In the method, the time slots group • «« ··; let's think about time groups. The sig-. ·: The signals are amplified in the amplifier means with the same gain factor. In this way, the number of amplifier means can be minimized.

* 4 · «« «25 Brief Description of the Drawings ···. The invention will now be described in more detail in conjunction with the preferred embodiments. with reference to the accompanying drawings, in which: T Figure 1 illustrates a prior art receiver, Fig. 2 illustrates the use of a prior art receiver, Fig. 3 illustrates a radio system employing a reception method according to the invention, Fig. 4 shows a receiver according to the invention, Fig. 5 shows 35 different gain areas used in a receiver according to the invention, 4 106670 Fig. 6 shows a target window to be formed for a received signal, and Fig. 7 shows a channel division.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a prior art receiver. The receiver comprises an antenna 130, a signal distribution means 131 and an amplifier means 132. The receiver further comprises a tuning means 133, a multiplexing means 134 and a signal processing means 135. The receiver antenna 130 is connected, for example, by cable, to the distribution means 131. in addition, each tuner means 133 communicates with the processing means 135 through its own multiplexer means 134. In practice, the receiver shown in the figure comprises three separate receivers, each receiving a signal from its own frequency band.

The receiver receives a radio frequency signal through its antenna 130. The received signal is applied from the antenna to the distribution means 131, which branch the signal to each amplifier means 132. The amplifier means amplify. . after which the amplified signal is applied to the tuning means. The tuning means 133 operate in broadband. From the tuning means 133, the signal is transmitted to · · ·: 20 to the multiplexing means 134, which divides the broadband signal into a plurality of narrowband signals. The multiplexed signal is generally in digital format, and the multiplexed signal is applied to the processing means 135 for encoding.

Figure 2 illustrates the use of a prior art receiver: amplifier means 132. Figure 10 is a graph depicting a change in the level of a received signal 25 between a receiver and a signal transmitter. **. as a function of the distance between the transmitter. Curve 20 describes the progress. · * ·. change in attenuation as a function of the distance between the receiver and the transmitter that transmitted the signal. The figure shows that signals of very different power arrive at the receiver. Receiver amplifier equipment

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The longer the signals arrive, the stronger the signals become:. receiver.

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Assume that a prior art receiver establishes a connection to the transmitter. In practice, the transmitter is a subscriber terminal, for example a mobile phone. The connection is initiated based on 35 random access bursts transmitted by the transmitter. When the receiver receives ac-cess bursts, the signal used is set to a specific frequency. Receiver 106670 selects the frequency used in connection with the received signal level. If the transmitter is located relatively far from the receiver, the connection signal is set at a frequency such that the signal goes to an amplifier means 132 that amplifies the signal relatively much. If, on the other hand, the transmitter is located relatively close to the receiver, the signal is set at a frequency such that, when the signal arrives at the receiver, the signal goes to an amplifier means 132 which amplifies the signal relatively little.

Figure 3 illustrates a radio system using a receive method according to the invention. The radio system comprises a plurality of subscriber terminal devices 201, 202, 203 and base stations 101. In addition, the radio system typically comprises a base station controller 300 and a mobile switching center 400, which is further connected to the PSTN network. The base station 101 of the figure typically comprises a plurality of receivers 100. The radio system shown is, for example, a GSM system 15 employing a TDMA multiple access method. In the TDMA multiple access method, signals are transmitted in time slots. The base stations 101 serve as receivers in the solution shown in the figure. Instead, the subscriber terminals 201-203 act as transmitters. The base station and the subscriber terminal form. . They communicate with each other using the signals they send.

FIG. 4 illustrates a receiver 100 according to the invention. The receiver at «'··' '· 100 is located in base station 101. The receiver comprises an antenna 130, signal distribution means 131, amplifier means 132, 136, tuner means 133, 140, channelization means 134 and signal processing means. 135. Antenna 130 '·· is connected to signal splitting means 131 which is still engaged: T: 25 to both amplifier means 132, 136. Amplifier means 132 is coupled via tuner means 133 to multiplexer 134. Instead, amplifier means 136. ···. is connected via tuner means 140 directly to processing means 135.

. ** ·. By means of its antenna 130, the receiver receives a radio frequency signal. The received signal is applied from the antenna to the signal distribution means 131, v .: 30, which splits the signal to the amplifier means 132, 136. The amplifier means amplifies the signal, after which each amplified signal is applied to its own tuner means 133, 140. Tuner means 133 operate broadband , and the tuning means 140 operate in narrowband. The signal from the tuning means 133 is applied to the multiplexing means 134. The channel-transmitted signal of the multiplexing means is generally in digital form. The channelized signal is further transmitted to processing means 135 which, for example, encodes the received signals. In addition, • · 6 106670 shows that the receiver uses gain control. The processing means 135 provide an gain control signal which is coupled to the broadband amplifier means 132.

In the embodiment shown in the figure, the dividing means 131 divides the signal received by the antenna 5 into two branches of the receiver. The first leg comprises at least one narrowband tuning means 140 having a large dynamic range. The receiver is adapted to generate an automatic gain control signal (AGC), which is applied to a narrowband amplifier means 136 having a large dynamic range size due to the use of an auto gain control signal 10.

The second leg of the receiver comprises at least one broadband tuning means 133 having a small dynamic range. Narrowband tuning means 140 are necessary at the receiver of the GSM type system, since the random access burst activating the connection can be transmitted anywhere in the coverage area of base station 101.

A random access burst is transmitted at a predetermined time interval and at a predetermined frequency. Typically, the access burst is transmitted in time slot zero. The level of the access burst can vary greatly depending on the situation. . jon. The connection is possible because the dynamic range of the narrowband receiver / 20 receiver arms is due to the automatic gain control 4 «4 <· 5! buy so large that the receiver can receive signals of very different power, such as access bursts. The magnitude of the received signal level «,. \: 'Is particularly affected by the distance of the subscriber terminal acting as the transmitter from the base station serving as the receiver. In addition, signal reflections a-: 25 cause changes in the signal power level.

The receiver of Figure 4 further comprises measuring means. 150 and positioning means 160. In the receiver shown in the figure, the measuring means ···. 150 and investment means 160 are in communication with processing means 135.

The '1' measuring means 150 are further connected to the amplifier means 136. The measuring color: 30 The lines 150 measure the activation signal used to establish the connection ···

Iin strength. The measuring means 150 also measure the strength of the signal establishing the connection after the connection is established. The purpose of the measurement is to determine the magnitude of the signal propagation attenuation. In the solution shown in the figure, the measuring means 150 measure the access burst transmitted by the transmitter 201 -203. Based on the measurement performed by the measuring means 150, it is possible for the amplifier means 136 to preset a gain factor of · · 106670 for a signal received from a particular time interval that communicates between the transmitter and the receiver.

The location means 160 places the connection signal on the basis of a strength measurement of the activation signal 5 made before the actual connection is established. Based on the measurement made, it is possible for the placement means 160 to place the low-signal, linking signals in the time slots whose signals are amplified by the amplifier means 132 with a relatively high gain factor. In addition, it is possible for the positioning means 160 to place signals having a high signal strength 10 in time slots, the signals contained therein being amplified by the amplifier means 132 with a relatively low gain factor. In practice, the foregoing means that the amplifier means 132 amplify signals having substantially equal propagation attenuation with the same amplification factor.

Figure 5 shows the various gain areas used in the receiver of the invention. The figure shows that the receiver has received signals of different intensities. The differences in signal strength are mainly due to the different distances between the transmitters and the receiver. Image-. . the section further illustrates a line 54 illustrating the average levels of received signals as a function of the distance between the transmitter and the receiver. The gain region of the receiver according to FIG. Ii is divided into three different regions which form slots. The placement means 160 comprise at least two sets of time slots. Each time slot group uses its own gain factor. The slots are divided in advance between the different gain areas. The Si-25 display means 160 place connection signals at appropriate time intervals based on the measurement made by the measurement means 150.

. ···. The formation of the time slot groups allows the dynamic range of the receiver to be divided into at least two parts such that the parts overlap T somewhat. At an overlapping portion of the dynamic range • ·: .v 30 of the signal to be measured, the positioning means 160 may place the signal in a time slot that is relatively amplified or relatively amplified. Preferably, the placement means 160 sets the signal to a time interval group having more than «free time slots. The measuring means 150 can dynamically change the size of the overlapping area based, for example, on the distribution of the signal level it measures, the amount of traffic, changes in the received signal level statistics or the quality of the received signal.

s 106670

Thus, the dynamic range is divided between three groups of slots, each group having its own gain factor. Thresholds 51, 52 are indicated in the figure between two sets of time slots. It is assumed that the receiver receives the signal transmitted by the subscriber terminal, shown in step 55 of Figure 5, and that the signal is amplified by a low gain factor. As the T-wide terminal moves away from the receiver, at some point the level of the received signal goes beyond the set threshold 51.

When the signal exceeds the limit 51, the time slot used by the signal is switched to another time slot containing 10 more amplifications of the signal. As the subscriber terminal approaches the receiver, the level of the signal received by the receiver must pass over boundary 52 before the time slot used by the signal is again changed to the original time slot group using a lower gain factor. If the receiver receives the signal shown in step 53 of FIG. 5 from the wide-area terminal, then it is possible to receive the signal transmitted by the subscriber-terminal 15 with a receiver branch having a low or high gain factor.

The threshold limits 51, 52 thus form the boundaries of the hysteresis region. Once the signal is set to a time slot, hysteresis allows sig-. . the volume is not immediately set to another time interval, even if the signal level • »'·” · 20 varies slightly. In addition, timers which prevent continuous switching of the time slot may be used for reception. Once the time slot change is done, a new change is made only after a while.

.. * · * Figure 6 shows a target window to be generated for a received signal. Because the dynamic ranges of the low gain receiver and the high gain time slot group are different, the low gain receiver cannot receive weak. ***. signal. Therefore, the target power control window must be within its range. *. «·. a jar with a low gain. Typically, the radio system seeks to minimize the transmit power used by the transmitter so that the quality of the • signal forming the connection is maintained. As the transmitter's transmit power ··· is reduced, the signal received by the receiver is also reduced. The figure shows that a receiver with high gain is capable of receiving signals of low power, whereby the target window can be positioned at relatively low signal levels. However, the target window is set so that even low signal levels are high enough to maintain good signal quality.

• · 9 106670

In a cellular radio network, different control channels are used in which different control information is transmitted. In GSM, a BCCH channel is used as a control channel for transmitting a BCCH signal. The narrowband receiver supports all time slots on the BCCH frequency. If the subscriber terminal is close to a base station, then the signal transmitted by the subscriber terminal probably does not need to be amplified very much in the receiver. In this situation, the signal of said subscriber terminal should be allocated from the broadband receiver a certain time interval, the signal contained therein being only slightly amplified by the amplifier means 132. However, it is assumed that the receiver's low gain 10 capacity is already full. It is further assumed that the signal transmitted by the subscriber terminal is not received in the overlapping area of the dynamic ranges, whereby the signal cannot be placed in any time slots containing a large amount of signal. In the above situation, the transmitter and the receiver communicate with each other on a traffic channel 15 on the BCCH frequency.

Essentially, the situation described above also arises in a hand-over situation where the signal belonging to the low gain group, i.e. the low gain group, should be transferred to the high gain group. If all the chickens in the high-gain group. . If the buses are already busy, after the handover, the traffic channel on the BCCH - «j '/ 20 frequency is used. If the slots group signals are amplified from the broadband and if all slots of the broadband slots group are occupied, the positioning means will place the signal to be measured on the frequency, ,,; | * which is received by the narrowband receiver branch.

Figure 7 shows the channel division used in the receiver. ^ Vis': *: It is seen that the broadband and narrowband receivers receive time slots containing signals of different frequencies. Broadband ···. however, a wideband and narrowband receiver receives signals from different time intervals. Instead, the narrowband receiver receives signals from each time slot. However, the signal received by the narrowband receiver • · v: 30 is the same frequency.

: ***: Although the invention has been described above with reference to the example of the accompanying drawings: ·, it is clear that the invention is not limited thereto, but is included. it can be modified in many ways within the scope of the inventive idea set forth in the appended claims.

Claims (28)

1. A receive method employing a TDMA multiple access method, receiving signals in slots for establishing connections, and receiving transmitted signals of different intensity in the time slots, and amplifying the received signals with a certain magnification factor, characterized by: at least two sets of time slots having different gain ratios, wherein the signals received from the slots of the same time slot group are amplified by an equal gain gain, and wherein the linking signal is placed in the slot group by measuring the received signal's strength. based on the signal strength measurement of the signal. Method according to claim 1, characterized in that the positioning of the signal in the time slot group is made on the basis of a signal strength or a corresponding measurement which makes it possible to determine the attenuation of the t1 signal caused by the The method according to claim 1, characterized in that the signal to be measured is received by a narrowband receiver. dia i *. The method of claim 1, characterized in that the random access burst initiating the connection is measured, and based on the strength of the measured signal, the actual connection signal is placed in the time slot group. The method according to claim 1, characterized in that the signal consisting of the signaling information is measured and the signal establishing the connection based on the strength of the measured signal: Y: is placed in a group of time intervals **. · · · A method according to claim 1, characterized in that, after the connection is established, the signal forming the connection is measured, and based on the strength of the measured signal, the connection signal is placed in the time slot group. 7. A method according to claim 1, characterized in that, when the signal strength of the measured signal is low, the signal forming the connection is placed in a time slot group, the signal of which is amplified by a relatively high gain factor. 8. A method according to claim 1, characterized in that, when the received signal is strong, the connection 5 signal is placed in a time slot group whose signal is amplified by a relatively low gain factor. 9. A method according to claim 1, characterized by dividing the dynamic range of the receiver into at least two parts of the receiver which overlaps somewhat, and when the intensity of the signal to be measured is overlapped by the dynamic portion of the dynamic region. A method according to claim 1, characterized by dividing the dynamic range of the receiver into at least two parts of the receiver which overlaps somewhat, and setting the connection signal to a range of slots containing a plurality of free time slots when the signal strength is measured. : m. • · · 10 106670 A method according to claim 1, characterized in that "V 20 that if the slots group signals are amplified from broadband and if" "! all slots in the above-mentioned slot group are occupied, placing a measurable signal on a frequency received at the narrowband receiver • ·: “receiver branch. • «· v A method according to claim 1, characterized in that the gain of the signals of the non-extreme time-slot groups is dynamically changed to form at least three overlapping timeslots of time slots. A method according to claim 1, characterized in that, by means of time slot groups, the dynamic range of the receiver is subdivided into some overlap, and at least two handovers are formed for each overlapping area. threshold, which can be dynamically resized. *: ··: 14. A receiver for use in a TDMA radio subsystem, which receives signals interleaved by means of which the receiver establishes communications, and which receives signals of different intensity in the time slots, comprising amplifier means (132, 136), which amplify the received signals with a certain magnitude gain, 12 106670 characterized in that the receiver is adapted to receive connection signals from time slots and to form at least two sets of time slots, and the receiver amplifier means (132, 136) amplify signals comprised by different - the means (132, 136) amplifying the signals comprising the same time slot group with an equal gain factor, and the receiver comprising measuring means (150) measuring the intensity of the signal received by the receiver, and 10, positioning means (160) for positioning the connection signal to the time slot group based on the strength measurement made on the received signal. Receiver according to claim 14, characterized in that the measuring means (150) measure the strength of the signal received by the receiver or use corresponding measurements, on the basis of which the positioning means (160) place the signal in the time slot group. A receiver according to claim 14, characterized by a wherein the receiver comprises narrowband tuning means (140) which receive a signal from the amplifier means (136) which is further exported to the measuring means I 150 · V (150). '' '; A receiver as claimed in claim 14, characterized in that the measuring means (150) measures the I: random access burst initiating the connection, based on the intensity of which the actual connection forming signal is placed in the time slot group. A receiver according to claim 14, characterized in that the measuring means (150) measures a · “*: signal needed for establishing a connection, which comprises signaling information and based on the intensity of which the actual connecting signal is placed in a time slot group. • · · The receiver of claim 14, characterized in that, after the connection is established, the measuring means (150) measures the connection signal, based on the strength of which the connection signal: · ··: is placed in the time slot group. Receiver according to claim 14, characterized in that, when the signal strength 35 of the signal measured by the measuring means (150) is small, the location means (160) places the connection signal 13 in a 106670 time slot group whose signal is amplified by the amplification means. A receiver according to claim 14, characterized in that, when the signal strength of the signal measured by the measuring means (150) is high, the positioning means (160) places the connection signal in a time slot group whose signal is amplified by the amplification means. Receiver according to claim 14, characterized in that the receiver divides its dynamic range into time slots into two 10 overlapping portions, and when the intensity of the signal measured by the measuring means (150) is overlapping, the positioning means (160) sets the communication signal to either of the overlapping portions. to the time slot group. A receiver as claimed in claim 14, characterized in that the receiver divides its dynamic region into slot groups at least two overlapping portions, and when the intensity of the signal measured by the measuring means (150) is overlapping the dynamic region, the location means (160) signal preferably to it II:. the slot group that contains the most free slots. ; 20 A receiver according to claim 14, characterized in that the receiver divides its dynamic region into parts that overlap something; and the overlapping area comprises at least two handover thresholds, the position of which may be dynamically changed by the receiver. A receiver according to claim 14, characterized in that the amplifier means (132) is a broadband amplifier whose amplification factor is adjusted based on measurement data obtained from the signal measurement of the measuring means (150). . · *. ·. The receiver of claim 14, characterized in that the amplifier means (136) is a narrowband amplifier that forms **: ** 30 parts of a narrowband branch of the receiver. The receiver of claim 26, characterized in that the amplifier means (132) is broadband, and the amplifier means (132) forms part of the receiver's broadband branch through which all of the time slots of the incoming time slot group are occupied. the placement means (160) position the measured signal at a frequency received at the narrowband receiver branch. 14 106670 A receiver according to claim 14, characterized in that the receiver is adapted to dynamically change the gain of the signals of the non-extreme time slot groups as the receiver forms at least three overlapping time slot groups in the time slots. «« Tl · «<<4 (« • {<(4 4 · 4 4 · · · · · • 1 • 1 · • «« • · · · · 1 · • · • «* 1 · ♦ · • · • · · · is 106670